The invention relates in general to welding and in particular to a new and useful transport device for welding wire feed at welding equipment, in particular arc shield-gas welding tools disposed as manipulators.
Welding equipment, in particular automatic welding machines or welding robots, have a disadvantage that, despite the diverse movements of the welding tool, the wire must be supplied to and emerge from the welding die or tip always at the same speed and with the same force. This is true in particular for arc shield-gas welding equipment. The welding die moves over a relatively long guide distance. In track welding, the welding die must often follow complicated paths in space, the welding wire guide being moved along. These changes of direction of the wire guide complicate the wire transport and lead to vibrations in the wire feed system even if the die moves fast. Due to these factors, the wire feed is no longer constant, and hence the welding quality suffers.
It is known for hand-held torches to use two mutually independent drives for the transport of the welding wire. The rear drive, arranged near the wire roll, then constitutes the main drive, which essentially determines the wire feed. The front drive is located near the welding die and, being a small size auxiliary drive, is integrated in the torch handle. Thereby mainly welding wires of soft materials susceptible to buckling are conveyed. It has been found in the practice that the known transport device cannot meet the requirements for constant welding wire supply. Besides, high motor loads result, which shorten the life of this device.